Hemorrhoids are swollen veins in the anal canal.
With internal hemorrhoids, you may see bright red streaks of blood on toilet paper or bright red blood in the toilet bowl after you have a normal bowel movement. You may see blood on the surface of the stool.
External hemorrhoids can get irritated and clot under the skin, causing a hard painful lump. This is called a thrombosed, or clotted, hemorrhoid.
Report the bleeding to your doctor, who may want to examine you before suggesting any treatment. It would be a good opportunity to discuss a weight loss program.